The present invention relates to the field of centrifugation in general, and more particularly to centrifuge tubes that also function as syringes.
The prior art contains numerous devices that provide for the extraction of fluid samples as well as their centrifugation. For example, U.S. Pat. No. 4,459,997 to Sarstedt discloses a blood extraction and centrifugation device that provides for the withdrawal of blood from a patient into a tube that can be used for centrifugation. The centrifugation tube is a simple straight-walled tube that does not contain a constricted region or provide for the use of density gradient material.
U.S. Pat. No. 4,020,831 to Adler discloses a syringe that can draw a specimen, and then allow disassembling of certain parts of the syringe so that the portion of the syringe holding the specimen can be placed in a centrifuge. The syringe also contains a plug of a specific density. During centrifugation, the specimen will separate so that lighter phases are above the plug, and heavier phases are below the plug. This device does not provide for easy removal of the separated phases, and does not provide for the use of a density gradient material.
In addition, U.S. Pat. No. 3,965,889 to Sachs discloses an apparatus for the sampling of blood and the separation of plasma. The syringe includes a thermosealable walled container with a medial restriction into which blood is drawn. After the blood is drawn into the container, the container is removed and placed in a carrier for centrifugation, after which the container can be sealed at the restriction to separate the phases of blood. This device requires the removal of the specimen container to a different carrier for centrifugation, thereby increasing the risk of contamination of the specimen.
There is thus a need in the art for a syringe that can be used to separate materials of different densities which is an integrated unit that does not require transfer of sample to a different container for centrifugation and therefore reduced risk of contamination. The present invention provides a sterile environment in which all required cell sorting manipulations can be carried out.